This invention relates to web handling machines such as plotters, recorders and sign makers wherein a web is fed longitudinally of itself by a pair of sprockets cooperating with holes in the two longitudinal side edge portions of the web, and deals more particularly with a web loading and feeding system for such a machine, including a related web construction and a method and apparatus for making the web, facilitating by way of visual aids the proper loading of a web onto the machine.
The present invention may be used with any one of various types of machines wherein a web is moved by a pair of sprocket wheels having pins, or teeth-like members, on their peripheries cooperating with rows of feed holes in the web's two side edge portions. In such machines it is usually essential to error free operation that the web be properly loaded in the machine so that the sprocket pins engage the correct web holes. This means that two corresponding pins of the two sprockets located in a common plane passing through the sprocket drive axis should engage two corresponding feed holes of the web located on a common line extending perpendicular to the edges of the web. Often, particularly when the web is very wide, it is difficult to determine by eye which sprocket pins correspond with one another and which holes on the opposite sides of the web correspond with one another, and as a result web loading errors can easily occur. Moreover, sometimes when a web loading error is made the web thereafter nevertheless appears to feed in an apparently normal manner so that errors introduced by the web loading may be ascribed to other causes and not quickly traced back to the faulty loading.
A general object of the invention is therefore to provide a visual means to enable a machine operator to easily visually determine the proper placement of a web when loading it onto the feed sprockets of a machine. Although, as mentioned above, this invention may be used with various different types of web handling devices it is particularly well suited for machines such as the sign making machine as shown in copending patent application Ser. No. 401,722, filed July 26, 1982, wherein the web is relatively wide and wherein in the course of a day's operation many different webs may be loaded onto the machine.
The invention also has as an object the provision of a web construction usable with a web handling machine to facilitate proper loading of it into the machine and has as a related object the provision of a method and apparatus for efficiently making such a web.
Other objects and advantages of the invention will be apparent from the following detailed description of the preferred embodiments and from the accompanying drawings.